Apparatus for simultaneously applying alternate fluid coatings to a traveling sheet material

ABSTRACT

An apparatus and method for applying alternate fluid coatings to a traveling sheet material simultaneously with the application of production coating along the remainder of the sheet surface. The alternate fluid coating is achieved by first applying a production coating to a furnish roll, doctoring the production coating from a strip of the furnish roll, applying an alternate fluid coating to this strip, and transferring the resulting coatings from the furnish roll to a traveling sheet. The apparatus comprises a furnish roll including coating means and an engageable doctor blade-coating pan in sequential contact with a portion or strip of the coated furnish roll surface.

United States Patent 1 Romaine [4 1 Aug. 20, 1974 APPARATUS FOR SIMULTANEOUSLY APPLYING ALTERNATE FLUID COATINGS TO A TRAVELING SHEET MATERIAL [75] Inventor: Douglas J. Romaine, Vancouver,

Wash.

[73] Assignee: Crown Zellerbach Corporation, San

Francisco, Calif.

22 Filed: Oct. 20, 1972 211 Appl. No.: 299,569

[52] U.S. Cl 118/104, 118/204, 118/262 [51] Int. Cl. 1305c l/08, B050 9/06 [58] Field of Search 118/204, 259, 203, 104,

[56] References Cited UNITED STATES PATENTS 2/1916 Erickson et a] 118/203 X 6/1939 Mueller 10/1950 Mackey 118/204 2,918,899 12/1959 Munton et a1. 118/259 X Primary ExaminerJohn P. McIntosh Attorney, Agent, or Firm-Thomas R. Lampe; Corwin R. Horton [5 7] ABSTRACT An apparatus and method for applying alternate fluid 13 Claims, 4 Drawing Figures APPARATUS FOR SIMULTANEOUSLY APPLYING ALTERNATE FLUID COATINGS TO A TRAVELING SHEET MATERIAL BACKGROUND OF THE INVENTION been the practice to transport the sheet material past various coating rolls continuously and to adjust the coating conditions of each individual step. Avery important link in such a continuous process is the apparatus transferring the surface coatings to the sheet material. Any fault or imperfection in the function of the apparatus which causes one step of the process to fail in any fashion results in a damaged or undesirable coating. In addition, any apparatus which provides multiple-step coatings enhances the possibility of undesirable end-result coatings and production stoppages.

Previously employed apparatus adapted for the application of surface coatings to continuously running sheet materials has been of limited utility for the purpose of applying, simultaneously, alternate or experimental coatings. During the application of alternate coating to a traveling sheet, it has been necessary to coat only a portion of the sheet by each consecutive applicator roll, therein varying the coating conditions fromstep-to-step. Applications exist in which it is desirable to provide production coatings alongside experimental coatings wherein these various coatings can be simultaneously transferred from a furnish roll to the moving sheet material in one operation. It is accordingly desirable to provide an apparatus and method by which a traveling sheet or web can be coated simultaneously with an alternate fluid coating side-by-side with a production coating.

Fluid coatings are applied to all types of sheet materials including paper and related web materials for any number of reasons, and among the advantages obtained thereby are improvements in printability, gloss, smoothness, opacity, brightness, feel, and masking of the web surface. Such coatings basically consist of pigment bound with an adhesive.

Coatings normally include such well-known pigments as barium sulfate, calcium carbonate, calcium silicate clay, satin white, diatomaceous silica, talc, titanium, and the like; and adhesives including, for example, the natural proteins, i.e., casein and soya; animal glue; starch, the synthetic adhesives; the paper latexes, i.e., styrene, butadiene, chloroprene, and the polyvinyl acetates. Various pigments and adhesives may be mixed for a particular coating application and may be employed with additional additives, such as setting agents, defoamers, waxes, and the like. Coatings may be applied in a number of layers and the preparation and formulation of these coating colors for paper applications are well-known in the art.

Paper webs may be coated on or off the papermaking machine and various methods and apparatuses for applying coatings to paper webs have been developed, for example, trailing blade coaters, air knife coaters, roll coaters, dip coaters, brush coaters, spray coaters, print coaters, strip coaters, and the like. Many variations in coating processes and in the design of coating apparatuses are known in the art.

- Notwithstanding the many variations in coating processes and respective apparatuses, it is desirable to have a process and apparatus which provide a means for applying at least one strip of alternate or experimental coating to a traveling web simultaneously with the application of a production coating. The simultaneous transfer from a furnish roll of an experimental or special alternate strip coating alongside production coatings to a traveling web with the only coating variable being the coating fluids is highly desirable for many applications.

SUMMARY It is, therefore, an object of the present invention to provide apparatus for the simultaneous transfer to a traveling web of alternate strip and production coatings along the full width of the web.

Another object is to provide apparatus for applying simultaneously, alternate strip and production coatings to a traveling web wherein all variables exclusive of the coating fluids are approximately constant.

Still another object is to provide apparatus for the simultaneous transfer to a traveling web of experimental strip coatings with a production coating along the remaining surface of the web.

A further object is to provide apparatus for sequentially removing a strip of production coating from a furnish roll and recoating the uncoated furnish roll strip with an alternate fluid coating.

The above and other objects are obtained according to a broader aspect of the present invention by providing a method and apparatus for applying an alternate fluid coating strip to a traveling web achieved by first applying a production coating to the furnish roll, doctoring a strip of the production coating from the furnish roll, and recoating the doctored strip with an alternate fluid coating, thus allowing simultaneous transfer of the alternate and production coatings to a traveling web.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the present invention is fully described below and is illustrated by accompanying drawings in which:

FIG. 1 is a side view, mostly diagrammatic, of a furnish roll, breast roll apparatus for coating a traveling web wherein the apparatus includes the doctor bladecoating tray of the invention in operational position.

FIG. 2 is a side view, mostly diagrammatic, of a furnish-metering roll coating apparatus including the doctor blade-coating tray of the invention in an engaged position.

FIG. 3 is a diagrammatic side view of a furnishapplicator roll mechanism with the doctor bladecoating tray apparatus of the invention in place against the furnish roll; and x FIG. 4 is a side view of the doctor blade-coating tray in an engaged position against a furnish roll.

DETAILED DESCRIPTION Referring to FIG. 1, a furnish roll 2 rotates with the lower portion inside a coating pan 4 wherein the furnish roll 2 contacts aproduction fluid coating level 6. A coating tray 8 and a doctor blade 9 associated therewith are positioned in contact with the rotating furnish roll 2. The coating tray 8 has a fluid coating conduit 10 for continuous alternate coating fluid supply. Due to its rotation, roll 2 is first coated with production coating along its full extent. Doctor blade 9 strips off the pro duction coating along a'predetermined portion of roll 2 and tray 8 subsequently applies the alternate coating to this portion. A traveling web 12 supported by guide roll 14 is coated by rotating furnish roll 2 subsequent to the doctor blade 9-coating tray 8 furnish roll contact with a strip of production coating and a strip of alternate coating. In this sequence of contact (furnish roll 2; doctor blade 9; coating tray 8; and traveling web 12), a simultaneous transfer of an alternate coating alongside a production coating extending over the entire web can be achieved. The traveling web 12 after contact coating from the furnish roll 2 is positioned by a breast roll 16 for exposure to an air knife 18 or other means wherein excessive coating is removed from the traveling web 12. I

The furnish roll coating apparatus as just described in connection with FIG. 1 is conventional except for the doctor blade 9 and coating tray 8 which comprises an embodiment of the invention. It is to be understood that other furnish roll coating apparatuses such as those of FIGS. 2 and 3 could be used in cooperation with the doctor blade 9-coating tray 8 embodiment.

In FIG. 2, an alternative arrangement is shown wherein a strip of production coating is suppled to a traveling web 32 by furnish roll 20 which has received the production coating from pan 22 having a coating level 24. Doctor blade 28 removes a strip of production coating from furnish roll 20 which is then replaced by an alternate coating from tray 26. Coating tray 26 can be adapted for continuous operation through a supply line 30. Web 32 contacts furnish roll 22 subsequent to passage of the surface of the furnish roll past the doctor blade-coating tray (28 and 26), so that the web receives a simultaneous transfer of an alternate and production coating which together cover the entire width thereof. Backing roll 34 rotates with and holds the traveling web 32 in place against the counter-rotating furnish roll 20 and downstream counter-rotating metering roll 36. All three rolls, furnish roll 20, backing roll 34 and metering roll 36, rotate in the same direction, but not necessarily at the same speed. Metering roll 36 is contacted by a total width doctor blade 38 subsequent to the traveling web 32 contact, thus removing surplus coating fluids which are caught in pan 40. r

In FIG. 3, an indirect furnish roll or nip roll coater is utilized in coordination with the alternate strip doctor blade-coating tray apparatus of the invention. Furnish roll 42 receives a productionfluid coating from pan 44 having a fluid level 46. A strip of the production coating is removed from the furnish roll 42 by the doctor blade 50 and is immediately recoated by tray 48 with an alternate coating. Tray 48 can be supplied continuously with coating fluid through line 52. The alternate strip and production coatings are simultaneously transferred to applicator roll 54 which, in turn, transfers the coating to a traveling web 58 held in contact with the applicator roll 54 by the backing roll 56. The doctor blade-coating tray (50-48) embodiment could also function in position with the applicator roll 54.

The present invention is concerned with apparatus and method for applying alternate strip coatings to a production-coated furnish roll, therein allowing a simultaneous transfer of these coatings to a traveling web (FIGS. 1, 2 and 3). Any conventional furnish roll apparatus can be utilized in coordination with the doctor blade-coating tray apparatus of this invention, as illustrated in the aformentioned figures and as identified by elements 9-8, 28-26,and 5048, respectively.

FIG. 4 is a more detailed, side view of the doctor blade-coating tray in place against a furnish roll 60. Doctor blade 62 is held in position by mounting 64 which is adjustable through adjustment rod 66 in a readily apparent manner. The furnish roll 60 is contacted by side strip seals 68 of coating tray 72. Bottom strip seal 70 is slightly recessed from contact with roll 60 but can be in direct contact if operating conditions so dictate. Coating tray 72 has an engageable adjustment rod 74 and'is movably mounted from shaft 76. The coating tray 72 has a coating supply line 78 for continuous operation.

One specific employment of the apparatus and method of the invention is relative to experimental coating under production conditions. The apparatus of this invention eliminates the need for cleaning production pans and piping, and then supplying a limited volume of experimental coating through the production apparatus. The present invention provides an apparatus which is not placed into operation until a desired experimental coating application is required. The doctor blade-coating tray can then be engaged in a selected position during a production run, thereby eliminating down time while allowing side-by-side experimental strip and production coatings along the entire width of the furnish roll which are simultaneously transferred to a traveling web. Multiple apparatuses according to the invention can be utilized in coordination with furnish roll wherein said apparatus is limited to narrow strip application or a relatively wide furnish roll.

Referring again to FIG. 4, the side and bottom strip seals (68 and 70) can be arranged to allow the coating tray to remain in an engaged position without hindering the production coating cycle. Side strip seals 68 contact the furnish roll 60 only in a thin contacting surface leaving a thin contact strip which the surplus fluid production coating on the furnish roll 60 quickly recovers. The bottom strip seal 70 is slightly recessed from the coated furnish roll 60 surface and does not interfere with the production coating but is sufficiently close to the furnish roll 60 to prevent alternate coating spill. The doctor blade 62 is not generally engaged until the experimental or alternate strip coating is in tray 72, therefore, the doctor blade 62 does not interfere with the production coating. The operational selectability allowed by leaving the coating'tray in position against the furnish roll 60 promotes timely and controled use.

The doctor blade-coating tray can be further modified through the use of vertical and diagonal partitions. Vertical partitions would permit multiple fluid coating from the same doctor blade-coating tray unit while a diagonal partition from the lower open end to the upper closed end would allow for decreased tray volume. In addition, the Teflon-type seal strips could be constructed from a more resilient material which would provide greater absorption of furnish roll vibration.

One embodiment of the invention provides an apparatus for applying alternate strip fluid coatings to a traveling sheet material, comprising, in combination: a furnish roll, a furnish roll-fluid coating means, at least one doctor blade and coating tray in aligned and sequential contact with a fluid-coated furnish roll surface, a sheet supply and means for traveling said sheet in contact with the coated furnish roll surface subsequent to the doctor blade and coating tray contact. Another embodiment of the invention provides an apparatus for applying alternate strip fluid coatings to a traveling sheet material, comprising, in combination: a furnish roll, a furnish roll fluid-coating means, at least one doctor blade and coating tray in aligned and sequential, engageable contact with a fluid-coated furnish roll surface, an applicator roll in contact with the fluid-coated furnish roll surface subsequent to the contact of the doctor blade and coating tray, sheet supply and means for traveling said sheet, said applicator roll having a transferred fluid-coated surface in contact with the traveling sheet subsequent to the furnish roll contact.

The apparatus according to the invention provides a side-by-side comparison of experimental coating with production coatings. These alternate strips and production coatings are achieved with most variables remaining constant since the transfer from the furnish roll to the traveling web is simultaneous. In experimental coatings, for example, frequently only minor changes are made in the experimental strip coating, thus the differences between the production coating and the experimental coating are very subtle, and require detailed variable control. In order to appreciate these subtle differences between the coatings, it is desirable to use exactly the same substrate, drying conditions, thus minimizing these and related variables for both the production and experimental coatings. These subtle differences are more fully demonstrated by the method and apparatus of the invention. The alternate or experimental strip coating apparatus can operate with as little volume as a few quarts of fluid or can be a continuous operation, depending upon the desired results. Other modifications of the inventive apparatus involve the width of the doctor blade relative to the width of the coating tray contact with the furnish roll. Experimental coating operations would normally require the two widths to be approximately the same; however, other alternate strip applications could necessitate variations of these respective widths. For example, the blade width can be from to 2 inches wider than the tray width in order to leave noncoated web on each side of the experimental coating for cutting or separating guides.

While the foregoing specification has set forth embodiments of the present invention in considerable detail for purpose of making a complete disclosure thereof, various other embodiments and modifications will occur to those skilled in the art, but will fall within the spirit and scope of the invention defined in the following claims.

What I claim is:

1. An apparatus for applying alternate strip fluid coatings to a traveling sheet material, comprising:

A movable furnish roll, furnish roll fluid-coating means, at least one doctor blade shorter than the furnish roll and a coating tray in aligned contact with the fluid-coated furnish roll circumferential surface, said doctor blade adapted to remove coating applied by said coating means from a portion of said furnish roll and said tray adapted to apply an alternate fluid-coating to said portion, an applicator roll in contact with the fluid-coated furnish roll circumferential surface and spaced downstream from the doctor blade and coating tray in the direction of movement of the furnish roll surface, a

6 sheet supply and means for traveling said sheet, said applicator roll circumferential surface in contact with the traveling sheet material and adapted to transfer the fluid from the furnish roll to the sheet material.

2. The apparatus according to claim 1 wherein the coating tray has an open end with said open end having a circumferential dimension of said furnish roll, said open end having furnish roll contact surfaces overlaid by nonabrasive seal strips.

3. The apparatus according to claim 2 wherein said coating tray has a coating fluid feed conduit for continuous operation.

4. The apparatus according to claim 2 wherein said coating tray has an engageable doctor blade attached to the bottom of said tray.

5. The apparatus according to claim 4 wherein said doctor blade is of about the same width as that of the tray open end.'

6. The apparatus according to claim 4 wherein the tray is positioned with the seal-stripped open inside walls in contact with the furnish roll and the doctor blade is in an engageable position relative to the rotating furnish roll prior to the tray contact.

7. Apparatus for applying alternate strip fluid coatings to sheet material, comprising:

movable furnish means including a furnish surface having a predetermined width engageable with said sheet material; means for coating said furnish surface with a first coating over substantially the full width thereof;

means including at least one doctor blade shorter than said furnish surface width for removing said coating from a portion of said furnish surface width; and

means in alignment with said doctor. blade for applying at least one alternate coating to said furnish surface portion, whereby subsequent engagement between said sheet material and said furnish means results in the transfer of at least one strip of alternate coating and adjacent first coating to said sheet material.

8. The apparatus of claim 7 wherein said furnish means comprises a rotatable furnish roll and said alternate coating applying means comprising a coating tray having an open end conforming to the circumferential dimension of said furnish roll and in communication with said funish roll.

9. The apparatus according to claim 8 wherein the coating tray open end is defined by roll contact surfaces overlaid with non-abrasive seal strips.

10. The apparatus according to claim 9 wherein said coating tray has a coating fluid feed conduit attached thereto.

11. The apparatus according to claim 9 wherein said doctor blade is attached to the bottom of said tray.

12. The apparatus according to claim 1 1 wherein said doctor blade is of substantially the same width as the width of the tray open end.

13. The apparatus according to claim 8 additionally comprising a backing roll urging the sheet material against the furnish roll and a metering roll engageable with said sheet material and having a full-width doctor blade in operative engagement therewith to remove coating transferred to the metering roll surface due to the metering roll contact with the sheet material. 

1. An apparatus for applying alternate strip fluid coatings to a traveling sheet material, comprising: A movable furnish roll, furnish roll fluid-coating means, at least one doctor blade shorter than the furnish roll and a coating tray in aligned contact with the fluid-coated furnish roll circumferential surface, said doctor blade adapted to remove coating applied by said coating means from a portion of said furnish roll and said tray adapted to apply an alternate fluid-coating to said portion, an applicator roll in contact with the fluid-coated furnish roll circumferential surface and spaced downstream from the doctor blade and coating tray in the direction of movement of the furnish roll surface, a sheet supply and means for traveling said sheet, said applicator roll circumferential surface in contact with the traveling sheet material and adapted to transfer the fluid from the furnish roll to the sheet material.
 2. The apparatus according to claim 1 wherein the coating tray has an open end with said open end having a circumferential dimension of said furnish roll, said open end having furnish roll contact surfaces overlaid by nonabrasive seal strips.
 3. The apparatus according to claim 2 wherein said coating tray has a coating fluid feed conduit for continuous operation.
 4. The apparatus according to claim 2 wherein said coating tray has an engageable doctor blade attached to the bottom of said tray.
 5. The apparatus according to claim 4 wherein said doctor blade is of about the same width as that of the tray open end.
 6. The apparatus according to claim 4 wherein the tray is positioned with the seal-stripped open inside walls in contact with the furnish roll and the doctor blade is in an engageable position relative to the rotating furnish roll prior to the tray contact.
 7. Apparatus for applying alternate strip fluid coatings to sheet material, comprising: movable furnish means including a furnish surface having a predetermined width engageable with said sheet material; means for coating said furnish surface with a first coating over substantially the full width thereof; means including at least one doctor blade shorter than said furnish surface width for removing said coating from a portion of said furnish surface width; and means in alignment with said doctor blade for applying at least one alternate coating to said furnish surface portion, whereby subsequent engagement between said sheet material aNd said furnish means results in the transfer of at least one strip of alternate coating and adjacent first coating to said sheet material.
 8. The apparatus of claim 7 wherein said furnish means comprises a rotatable furnish roll and said alternate coating applying means comprising a coating tray having an open end conforming to the circumferential dimension of said furnish roll and in communication with said funish roll.
 9. The apparatus according to claim 8 wherein the coating tray open end is defined by roll contact surfaces overlaid with non-abrasive seal strips.
 10. The apparatus according to claim 9 wherein said coating tray has a coating fluid feed conduit attached thereto.
 11. The apparatus according to claim 9 wherein said doctor blade is attached to the bottom of said tray.
 12. The apparatus according to claim 11 wherein said doctor blade is of substantially the same width as the width of the tray open end.
 13. The apparatus according to claim 8 additionally comprising a backing roll urging the sheet material against the furnish roll and a metering roll engageable with said sheet material and having a full-width doctor blade in operative engagement therewith to remove coating transferred to the metering roll surface due to the metering roll contact with the sheet material. 